Itates pat



MW. 4, 1930. I J, c. BA 1,780,415

BREAKER MEGHAN'I SM Filed Jan. 5, 1927 Patented Nov. 4, l13

J'GEN C. BAKEEI, @F LAKE BLUFF, ILLENGIS, ASSIGNOR TQ FANSTEEQ RGDUCTQ @011- PANY, INC, 035

NGRTH CHIGAGO, ILLHTQIS, A GQEPURATKQN @F "YEW MECHANIQH Application filed January 8, 1592?. Serial No. 158,48fi.

My invention relates to breaker mechanisms and the like, such for example as are used for circuit breakers in automobile ignition systems, and more particularly to an improved construction in the breaker arm.

The main object of my invention is to 130- vide an improved breaker mechanism aving a breaker arm of extremely compact construction, which facilitates its use when compactness is advantageous and the necessary arrangement of parts is crowded.

Another object of my invention is to provide a breaker arm wherein the contact disc may be of heavier and stronger material and still be compact and well balanced and less susceptible to twisting from its center.

Another object of my invention is to provide a breaker arm wherein the contact disc is secured and supported in part b the mode of mechanical engagement with t e'breaker arm independent of its usual welded connection.

In most breaker mechanisms it is necessary to have a compact arrangement of parts to facilitate rapid and accurate action due to the high frequency at which the breaks occur and the high rate of speed at which the mechanism operates. A compact arrangement of parts is also desirable for the reason that it promotes economy when these devices are manufactured on a large production basis. It may seem that 1 3- of an inch does not materially aid in compactness, but in most breaker mechanisms it has been found that my invention makes possible an arrangement of parts whereby the breaker arm assembly is readily adaptable to use in a mechanism of crowded nature, and at the same time pro- Vides an arm of sufiicient strength. In the manufacture of arms it has been the practice to construct them with the tungsten contact points mounted on a raised circular spot whereby the contact is beyond the center line of the arm and is quite outstanding. L

In attaining the foregoing features within my invention, ll mount the contact in a depression in the arm, rather than elevate it.

Further objects, features and advantages will readily become apparent through the projected a distance following detailed description and accompanying drawings, in which Fig. 1 1s a horizontal longitudinal section taken along the medial line of the breaker arm;

Fig. 2 is a transverse section the line 22 of Fig. 1;

lFi 3 is a view similar to Fig. 2, but showing t e elements in their disassociated positions just prior to assembling; and

Fig. 4 is a sectional plan view of a breaker mechanism showing the arm of my invention assembled therewith.

Referring to the drawings in which like reference characters designate like parts throughout the several views, a breaker arm 10 shown in Fig. 1 is of the type used in the circuit breaker mechanism of a standard automobile ignition system. It is stamped from sheet metal and preferably nickeled to prevent rust. The arm is in the general form of a channel, the flanges 11 having holes 12 at one end for the pivot pin, while the web 10' at the same end has an oifset 13 providing anchorage for the spring. At the free end of the arm the web 10 is provided with a depression 14 instead of the usual raised spot or table commonly provided. A contact disc 15 is provided of tungsten or other suitable metal having a diameter substantially the same as that of the depression 14, so that when the contact is placed in the depression, the depression acts as a jig to center the contact in its proper place on the web of the arm. A very thin disc 16 of welding medium is used in the welding process, which is described in my copendin application, Serial No. 37,632, filed June 1 1925.

A typicalbreaker mechanism assembly emtaken along bodying my improved breaker arm is shown in Fig. 4-. Here a rotating cam 20 having four points engages the roller 21 of the breaker arm 10. A. suitably mounted spring 22 engages the ofiset portion 13 of the breaker arm and maintains a movable contact 23 in closed relation with a stationary contact 24 suitably mounted in the mechanism.

Referring to Fig. 2, the depression 14 in which the contact point 15 resides, will be seen, afiords a more compact arrangement than if the contact 15 were mounted on a pedestal instead of in the depression. This compactness is very desirable for many reasons before stated.

When the contact is mounted in the usual and commonly known manner-that is, on a raised circular spot, the bottom of the con tact is- Welded to this spot, which places the bottom of the contact quite a bit above the surface of the breaker arm. Consequently, in employing a contact member of suflicient thickness to give satisfaction in service it will be seen that the top of the contact is thereby elevated a great distance above the surface of the breaker arm. If adepression is provided in the breaker arm and the bottom of the contact member is welded in said depression, the top of the contact member will consequently be lowered to a position imuch nearer the surface of the breaker arm. In this way the maximum of compactness is attained and a heavy, serviceable contact member may be utilized in less space.

It is also obvious that the mounting of the contact point 15 in the depression14- places the contact more directly in line with the center of the rotating axis of the arm, pro viding a slightly more balanced construction throughout. Through the use of my con; struction, I am enabled to use a thicker disc and at the same time increase the compactness of the construction. This lengthens the i life of the breaker arm, because when the the contact point is worn out it is necessary to replace the whole arm. The provision of a stronger, more stable and thicker contact point obviously aids in this respect.

The described method of mounting the contact point 15 in the depression 14: provides a certain degree of mechanical support. through the engagement of the wall of depression with the circumferential wall of the disc 15. Thus, if a blow is in any manner directed to one edge of the contact member tending to force it from its centered position on the breaker arm, the side walls of the depression will aid materially in maintaining the contact in position and relieving any stress or strain which might ordinarily fall on the weld.

In welding the bottom of the contact point 15 to the'bottom of the depression 1 1 a oer-o tain amount of the weld will take place around the edges of the depression which Will also aid materially in increasing the rigidity of the contact member in respect to the breaker arm.

I claim:

1. Incombination, a breaker arm provided with a centering depression, a contact point adapted to fit in said depression, and to extend slightly above the surface of the breaker arm, said contact point being welded both to the entire bottom of the depressionand to the sides thereof, whereby a maximum welded breaker arm, said contact point being welded both to the entire bottom of the depression and to the sides thereof, whereby a maximum welded area is obtained, the contact point is centered, and a minimum amount of space is required.

In witness whereof, I hereunto subscribe my name this 29th day of December, 1926. JOHN G. BAKER. 

